SSI Decompression Diving Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer highlights that a deeper ascent increases on-gassing in divers. On-gassing refers to the absorption of inert gases, such as nitrogen, into the body's tissues under pressure during a dive. As divers descend to greater depths, the pressure increases, which causes more gas to dissolve in their tissues.

When a diver ascends quickly from a deeper depth, the pressure decreases rapidly, and the gases that have been absorbed during the dive start to come out of the solution. If the ascent is not managed properly, it can lead to a situation where the rate of gas coming out of the tissues exceeds the body's ability to safely eliminate it, resulting in decompression sickness.

Conversely, ascending more slowly, especially from deeper depths, allows the body to off-gas (release the absorbed gases) more safely without accumulating excess nitrogen in the tissues. Therefore, understanding this relationship between depth, ascent rates, and on-gassing is crucial for safe diving practices.